A staircase is a structure used for ascending and descending between different levels of a building. It is typically composed of a series of steps, which can be made of wood, metal, or stone. The term 'stairway' is an 8-letter word for a staircase, while 'steps' is a 5-letter word for the individual components of a staircase. An escalator is a 9-letter word for a moving staircase, while a companionway is a 12-letter word for a staircase that connects two decks of a ship. Finally, a LADDER is a 6-letter word for a structure used to climb up and down, usually consisting of two side rails connected by several rungs.